Energy Losses In System Research Articles

МНОЖЕСТВЕННЫЙ ДОСТУП В БЕСПРОВОДНЫХ КАНАЛАХ С ИСПОЛЬЗОВАНИЕМ НЕОРТОГОНАЛЬНОГО КОДИРОВАНИЯ И ЧАСТОТНОГО ПЕРЕМЕЖЕНИЯ

Code division multiple access (CDMA) is currently considered as one of the promising technologies that can significantly improve the efficiency of modern and future communication networks. In code division multiple access systems, users can share a dedicated space-frequency-time resource to simultaneously transmit their own traffic. To ensure the separation of individual user streams on the receiving side, each user is provided with his own code sequence embedded in the broadband signal transmitted by this user, the spectrum of which, as a rule, occupies the entire allocated frequency band. When centimeter-and- millimeter wave wireless channels are used as the transmission medium, such factors as fading, multipath, and Doppler scatter can significantly degrade the performance of a code division multiple access system. The standard solution in this situation is to combine code division multiple access with OFDM (orthogonal frequency division multiplexing) technology, known as multicarrier CDMA (MC-CDMA). To ensure the acceptable level of performance of multiple access systems under oversaturated conditions, many novel approaches based on the use of non-orthogonal multiple access (NOMA) have been proposed. The paper considers a variant of multiple access with non-orthogonal coding that is close in approach to sparse coding multiple access (SCMA). The proposed access procedure is based on dividing the allocated time-frequency resource into relatively small clusters and sharing each cluster with its own group of users, equipped with a non-orthogonal cluster code with the ability to change the loading factor. For the proposed class of cluster codes, a general encoding and decoding scheme is presented. Examples of specific cluster code constructions and numerical results are given that allow one to get a number of the parameters for tradeoffs between an increase of the loading factor in the system and additional energy loss.

Probabilistic optimal planning of dispatchable distributed generator units in distribution systems using a multi-objective velocity-based butterfly optimization algorithm

Nowadays, because of the enormous increase in load demand, the electrical distribution system faces problems like poor system efficiency due to high I2R losses and poor voltage profile. Therefore, distribution system operators are looking for various alternatives for enhancing system efficiency & voltage profile. Distributed generation (DGs) technology has recently been the focus of several researchers due to its enormous technological advantages in mitigating the above problems. In this article, an approach is presented for the optimal integration of dispatchable distributed generations (DDG): PV-BESS (Photovoltaic System-Battery energy storage system), WT-Biomass (Wind Turbine) units in the distribution system in the presence of optimal network reconfiguration. Distribution generations like PV & WT are non-dispatchable in nature due to the intermittency nature of solar radiance and wind speed. The PV unit is supported by BESS, while the WT unit is supported by Biomass to make the PV and WT units dispatchable. Therefore, the paper's main intent is to determine the best locations & best sizes of PV-BES, Wind -Biomass units in the distribution system in the presence of network reconfiguration considering the time-varying 24-hour load pattern, probabilistic nature of solar irradiance & wind speed. To reduce system energy loss, voltage deviation index, and annual economic loss, a multi-objective pareto-based velocity butterfly optimization algorithm (MOVBOA) is used. IEEE 33,69 & 118 bus test systems are being used to implement the proposed approach. The MOVBOA algorithm gives better results for solving the problem than the multi-objective Butterfly optimization algorithm (MOBOA) & Non-dominated sorting genetic algorithm (NSGA-II).

A Variable Pressure Multi-Pressure Rail System Design for Agricultural Applications

This paper presents a solution for reducing energy loss in the hydraulic control system of agricultural tractors and their implements. The solution is referred to as a multi-pressure rail (MPR) and provides power to the hydraulic functions following a pressure control logic, as opposed to the traditional flow control logic typical of hydraulic systems used in off-road vehicles. The proposed hydraulic control system allows for elimination of redundant flow control valves in the state-of-the-art system, which cause excessive throttling losses leading to poor overall energy efficiency. Related work on MPR technology targets construction vehicles, where the MPR solution can allow energy recovery during overrunning loads and better engine management. This paper alternatively addresses the case of agricultural applications where functions mostly operate under resistive load conditions with slow dynamics, which offers an opportunity to target throttle losses. For this purpose, the paper introduces a variable pressure control strategy to handle the instantaneous pressure at each rail. To develop both the controller and the hydraulic system architecture, a stationary test rig is conceived and used to validate a numerical simulation model of the MPR system and its control strategy. Particular focus is given to the dynamic behavior of the system during the switches of a function between different pressure rails, which needs to ensure reduced oscillations of the flow provided to each hydraulic function. Once validated, the simulation model is used to predict the energy savings of the MPR solution in an actual application: a 435 hp hydraulic tractor powering a 16-row planter, for which operating features during typical drive cycles were available to the authors. The results show up to 59% total power reduction at the pump shaft, corresponding to 89.8% system efficiency gain.

Numerical study on the dynamic fracture of explosively driven cylindrical shells

Research on the expansion and fracture of explosively driven metal shells has been a key issue in weapon development and structural protection. It is important to study and predict the failure mode, fracture mechanism, and fragment distribution characteristics of explosively driven metal shells. In this study, we used the finite element-smoothed particle hydrodynamics (FE-SPH) adaptive method and the fluid–structure interaction method to perform a three-dimensional numerical simulation of the expansion and fracture of a metal cylindrical shell. Our method combined the advantages of the FEM and SPH, avoiding system mass loss, energy loss, and element distortion; in addition, the proposed method had a good simulation effect on the interaction between detonation waves and the cylindrical shell. The simulated detonation wave propagation, shell damage morphology, and fragment velocity distribution were in good agreement with theoretical and experimental results. We divided the fragments into three regions based on their shape characteristics. We analyzed the failure mode and formation process of fragments in different regions. The numerical results reproduced the phenomenon in which cracks initiated from the inner surface and extended to the outer surface of the cylindrical shell along the 45° or 135° shear direction. In addition, fragments composed of elements are identified, and the mass and characteristic lengths of typical fragments at a stable time are provided. Furthermore, the mass and size distribution characteristics of the fragments were explored, and the variation in the fitting results of the classical distribution function under different explosion pressures was examined. Finally, based on mathematical derivation, the distribution formula of fragment velocity was improved. The improved formula provided higher accuracy and could be used to analyze any metal cylindrical shells with different length-to-diameter ratios.

Numerical study of the energy loss in the bulb tubular pump system focusing on the off-design conditions based on combined energy analysis methods

The unsteady flow characteristics of the low-head bulb tubular pump highly affects the operation efficiency and stability of the whole system. The purpose of this paper is to investigate the dominating loss area in a typical tubular pump using the combined energy analysis methods. The transient multi-condition flow through the pump system is simulated based on N–S equation integrating SST k-ω model. The power loss characteristics of each flow passage component are analyzed in terms of total pressure variation, entropy production and energy balance equation. The turbulent entropy generation power (PSD') in the entropy production and the turbulent kinetic energy production (PL3) of the energy balance equation are the primary source of power loss, indicating that the fully developed turbulent flow tends to generate considerable loss in the pump system, followed by the power loss of solid wall (PSW and PLW). The distribution of power loss in the impeller and diffuser was comprehensively exhibited and it was found that the undesirable flow patterns are mainly caused by blades and walls. The rim region in impeller domain with volume fraction of 15% induces the energy loss of approximately 45% due to the presence of solid wall and tip leakage vortex (TLV). Furthermore, the individual grid volume is considered to better locate and visualize regions with our great interest, and a number of typical vortex structures are identified under several flow rates showing that the positive attack angle is more likely to caused flow instability and energy loss at low flow rate condition.

Event-Triggered Neural-Predictor-Based FCS-MPC for MMC

Traditional predictive control schemes dominated the research field of numerous power electronic applications over the past few years, since they usually lead to control solutions with good dynamic and steady results. However, these solutions strongly depend on the available knowledge of the control system (e.g., accurate modeling information), which often results in the lack of robustness in the presence of parametric uncertainties. Furthermore, unnecessary energy loss heavily correlates with high switching frequency, which directly affects efficiency. Aiming to cumbersome aforementioned scarcities, this letter is concerned with a novel approach to the controller design for a modular multilevel converter, which makes use of event-triggered neural-predictor-based finite-control-set model-predictive control methodology under low-switching-frequency operation. The salient feature of the proposed controller is that the uncertainties and unnecessary energy loss in practical systems can be explicitly dealt with, while keeping the switching frequency in a low value. Finally, steady-state and transient-state performance tests together with the analysis of the simulation and experimental results confirm the interest of the proposal, and the results found are promising and motivate further research in this field.

Economic Viability of Energy Communities versus Distributed Prosumers

As distribution grids are made to accommodate significant amounts of renewable energy resources, the power system evolves from a classical producer-consumer scheme to a new one that includes individual prosumers or energy communities. This article contributes to the exploration of the solution to the dilemma of whether to be a distributed prosumer or an energy community prosumer by comparing the profitability of these two business models. To achieve this goal, a high-resolution methodology is created for measuring economic performance via proposed indices under different development scenarios of renewable proliferation and various network configurations. The developed methodology considers today’s electricity billing and renewable support scheme net metering. The results indicate that, first, the energy community is a more profitable framework than the individual distributed prosumer: avoided costs for energy community are, on average, 20% higher than for the individual, resulting in a payback period of the energy community that is about two times shorter than for owners of rooftop installations. Such promising results should encourage ordinary consumers to be members of energy communities. Second, the energy losses in the power distribution system are slightly higher for the case of energy communities rather than individual prosumers, yet the difference is insignificant, about 0.2%. Third, regulatory barriers shall be removed to enable participation of Latvian prosumers and distribution system operators to the energy communities, as it will benefit all the stakeholders and facilitate economically efficient energy transition. The results of this study could be adopted by decision-makers, such as government agencies, companies, and solar and wind turbine owners.

Energy audit and conservation of Dental college – A case study

Power is a lifeline for the industry as well as to the individual citizen. With industrial growth of about 10 %, the power demand is surging very rapidly from last decade. With limited resources of power generation and lack of planning resulted into power shortages throughout the states. Unprecedented powercrisis is hindering the socio-economical growth of almost all states. The remedy for this power crisis is seen by the planner at Centre and states only in the two option. Addition of power capacity. Enforcing disparate load shedding. There is total disregard shown to the time tested option of Energy Efficiency improvement at various stages. (Like in generation, T & D, and end use) Reduction of avoidable energy losses in distribution system. Demand side management. Implementation and Monitoring of Energy efficiency improvement program. Bharti Vidyapeeth University Medical campus, Dhankawadi includes many colleges i.e. Medical, Dental, Rajiv Gandhi Biotechnology, Ayurved, Homeopathy college. Being High Tension consumer having Contract Demand of 200KVA, its monthly average electricity bill is Rs. 6,84,908/-. Sanctioned Demand is 344KVA and connected load is 413kW. Some of the major electricity consuming systems are Illumination, Heating equipment, Water pumping system, Air Compressor, Air conditioners. So, the present paper represents the overview of energy audit and conservation programme carried out at Bharati Vidyapeeth University Dental college campus. This study has resulted in exploring the overall energy and thus cost saving potential of 10 % with simple payback period of months. The outcome of this study and the implementation of the suggestions are discussed with the management and other concerned staff. The suggestions incorporated in Energy Audit report are technically feasible as well as financially viable.

Optimal design of full order state observer for active surge control in centrifugal compressors using genetic algorithm

This paper presents the design of a genetic algorithm (GA) based full order state observer for a compressor system. The observer measures the compressor system parameters and computes the difference between the measured output and the setpoint, which is used as feedback to the active surge controller. The proposed control structure with a GA tuned compressor characteristic is required to minimize system oscillations and energy losses induced by the piston actuation gas recycling technique. The design method for GA based full order observer begins with a state observer modelling, observer error estimation based on the magnitude of fluid friction and mechanical effects on measured parameters. The aim of the controller is to regulate the compressor driver speed such that the measured output achieves its required set point. In order to achieve a maximum compressor operating capacity, the compressor characteristics were optimized using GA, where the mass flow was maximized to improve the compressor efficiency. Simulations were carried out, and results showed the viability of GA based full order state observer compared with the piston actuation recycle method to control active surge in centrifugal compressor systems

A critical analysis of power conditions in sucker-rod pumping systems

The most decisive constituent of operating expenditures in sucker-rod pumping operations is related to the system's electric power use as most installations are driven by electric motors. Consequently, the reduction of operating costs can be translated to the reduction of energy losses both downhole and on the surface. Therefore, the energy efficiency of the surface and downhole components of the pumping system as well as the overall system efficiency play a big role in maximizing profits. The paper presents a critical analysis of the energy efficiency of the individual components of the sucker-rod pumping system and introduces novel models to find the system's total efficiency. The typical energy losses in the sucker-rod pumping system's main components (the downhole pump, the sucker-rod string, the surface pumping unit, the gearbox, the V-belt drive, and the prime mover) are discussed in detail. It is demonstrated that the level of the pumping unit's counterbalancing as well as any inertial effects do not impact on the net gearbox torques and on the required average mechanical output power of the motor. The energy consumption of the electric motor, however, is affected by the pumping unit's counterbalancing and the inertial effects because of the changes in motor efficiency due its variable loading within the pumping cycle. The system's useful output power is performed by the downhole pump when it lifts the produced liquid to the surface. The paper demonstrates that the so-called hydraulic power, calculated from the increase of the produced liquid's potential energy, is a reliable indicator of the system's useful power. Using the hydraulic power together with the electric power taken from the power supply permits an easy way to assess the over-all energy efficiency of the pumping system. The paper proposes several other variants of system efficiency calculations; they are based on the fact that all components of the pumping system are connected in series to each other. Sizing of electric motors for sucker-rod pumping installations is normally done with the use of a cyclic load factor (CLF) that accounts for the fluctuations in motor load during the pumping cycle. Originally, CLFs were found from the variation of motor current, but mechanical CLFs based on net gearbox torques are much more practical to use. This practice is fully justified in the paper by proving that the correlation between the motor's real current and its net torque loading is nearly linear. It is further shown that the safety of sucker-rod pumping installation design is improved if the electric motor is sized with the use of a mechanical CLF because that case gives the highest required nameplate motor power. • A critical analysis of the energy efficiency of the individual components of the sucker-rod pumping system is presented. • Novel models to calculate the over-all system efficiency of sucker-rod pumping systems are introduced and demonstrated. • The effects of counterbalancing on net gearbox torques and on the motor's mechanical power are evaluated. • Hydraulic power, representing the increase of the produced liquid's potential energy, is a reliable indicator of the system's useful power. • The use of mechanical instead of electrical CLFs to size electric motors is fully justified.

An Effective Fault Detection Method for HVAC Systems Using the LSTM-SVDD Algorithm

Fault detection in heating, ventilation and air-conditioning (HVAC) systems can effectively prevent equipment damage and system energy loss, and enhance the stability and reliability of system operation. However, existing fault detection strategies have not realized high effectiveness, mainly due to the time-delay characteristics of HVAC system faults and the lack of system-fault operation data. Therefore, aiming at the time delay of system faults and the lack of actual system-fault operation data, this paper proposes a fault detection method that combines a system simulation model and an intelligent detection algorithm. The method first uses the Modelica modeling language to build a scalable simulation model of the system to obtain fault data that are not easily accessible in practice. The long short-term memory-support vector data description (LSTM-SVDD) algorithm is then applied to detect faults in real time by dynamically adjusting the fault residuals according to the absolute difference between the predicted and actual values. The experimental results show that the LSTM-SVDD method improves the average detection accuracy by 9.675% and 9.85% over the classical LSTM network and the extreme gradient boosting (XGBoost) method, respectively, under different fault levels.

A Novel Analytical Approach for Optimal Integration of Renewable Energy Sources in Distribution Systems

The present research article focuses on an analytically based method for the optimal allocation and sizing of a renewable energy source (RES) capable of injecting both active and reactive powers in the distribution network. The placement of distributed generation (DG) in the distribution network reduces the magnitude of branch current in between the reference bus and the bus where DG is to be installed. Due to this, system power loss decreases significantly. The proposed method considers different levels of load in addition to peak load demand. The goal of the developed method is to minimize system losses by optimal DG allocations. In the proposed method, the optimum size of the DG is obtained on the basis of maximum loss saving criterion. For the execution of proposed method, only a base case load flow solution is required. The developed method has been tested on IEEE 69-bus and 33-bus radial distribution networks. On the basis of obtained results, it has been realized that the developed method is more capable of diminishing system energy losses.

A novel range telescope concept for proton CT

Proton beam therapy can potentially offer improved treatment for cancers of the head and neck and in paediatric patients. There has been a sharp uptake of proton beam therapy in recent years as improved delivery techniques and patient benefits are observed. However, treatments are currently planned using conventional x-ray CT images due to the absence of devices able to perform high quality proton computed tomography (pCT) under realistic clinical conditions. A new plastic-scintillator-based range telescope concept, named ASTRA, is proposed here to measure the proton’s energy loss in a pCT system. Simulations conducted using GEANT4 yield an expected energy resolution of 0.7%. If calorimetric information is used the energy resolution could be further improved to about 0.5%. In addition, the ability of ASTRA to track multiple protons simultaneously is presented. Due to its fast components, ASTRA is expected to reach unprecedented data collection rates, similar to 108 protons/s. The performance of ASTRA has also been tested by simulating the imaging of phantoms. The results show excellent image contrast and relative stopping power reconstruction.

ИССЛЕДОВАНИЕ КОМПЛЕКСНОГО ВЛИЯНИЯ ЭКСПЛУАТАЦИОННЫХ ПОКАЗАТЕЛЕЙ НА ПОТЕРИ ЭЛЕКТРИЧЕСКОЙ ЭНЕРГИИ В КОНТАКТНОЙ СЕТИ

With the use of mathematical technique of correlation analysis the authors have selected two parameters - turnover of goods and average service speed, among many operating indicators of an electrified railway section that affect energy losses in traction power system. In operative environment the authors suggest to use a catenary suspension mounting scheme that is optimal in terms of minimization of energy losses in traction power system on the basis of a sample of the considered factors with a determined confidence level.

Impact of Hydraulic System Stiffness on Its Energy Losses and Its Efficiency in Positioning Mechanical Systems

Hydraulic steering systems for mechanical devices, for example, manipulators or vehicle steering systems, should be able to achieve high positioning precision with high energy efficiency. However, this condition is very often not met in practical applications. This is usually due to the stiffness of the hydraulic system being too low. As a result, additional corrections are required to achieve the required positioning precision. Unfortunately, this means additional energy losses in the hydraulic control system. In this study, this problem is presented using the example of a hydraulic steering system for an articulated frame steer vehicle. This hydraulic steering system should provide the required directional stability for road traffic safety reasons. So far, this issue, connected mainly with the harmful phenomenon of so-called vehicle snaking behaviour, has not been solved sufficiently practically. To meet the needs of industrial practice, taking into account the current global state of knowledge and technology, Wrocław University of Science and Technology is performing comprehensive experimental and computational studies on the snaking behaviour of an articulated frame steer wheeled commercial vehicle. The results of these tests and analyses showed that the main cause of problems that lead to the snaking behaviour of this vehicle class is the effective torsional stiffness of the hydraulic steering system. For this reason, a novel mathematical model of the effective torsional stiffness was developed and validated. This model comprehensively took into account all important mechanical and hydraulic factors that affect the stiffness of a hydraulic system, resulting in the examined snaking behaviour. Because of this, it is possible at the design stage to select the optimal parameters of the hydraulic steering system to minimise any adverse influence on the snaking behaviour of articulated frame steer wheeled vehicles. This leads to minimising the number of required corrections and minimising energy losses in this hydraulic steering system. The innovative model presented in the article can be used to optimise positioning accuracy, for example, in manipulators and any mechanical system with hydraulic steering of any system of any mechanical parts.

Performance Analysis of a Rooftop Hybrid Connected Solar PV System

In the present work, a 5-kW hybrid PV solar system was installed on the roof of a house in Diyala, Iraq (33.77° N, 45.14° E elevation 44 m). The system consists of two strings, where each string consists of nine polycrystalline PV modules with 355 Wp in series, and the two strings are in parallel. The energy storage system (ESS) consists of two parallel strings, each with four 12 V and 150 Ah tubular deep cycle batteries in series. A hybrid inverter of 5 kW rated power was operated in different modes. The results showed that May’s monthly energy consumption was about 822.9 and 1085 kWh, respectively. The percentage distribution of the DC energy produced was about 1% system energy losses, 27.9% was used to charge the ESS, 34.3% was used to feed the grid, and the remaining 37.64% was used to share the load. The energy percentage sharing the load was 16.67% from ESS, 33.33% from the PV system, and 50% purchased. The average daily reference, array, and final yields were 6.07, 4.327, and 3.991 h/day, respectively. The average array and load efficiencies were 12.3% and 92.24%, with the performance ratio at 65.4%.

High-power switching device based on field emission mechanism fabricated using highly crystalline single-walled carbon nanotubes

Since the Great East Japan Earthquake in 2011, there has been a growing interest in energy conservation all over the world. To build a society centered on renewable energy, it is essential to obtain inexpensive and stable renewable energy, and completely eliminate energy loss in the energy utilization system for conserving energy optimally. Towards the construction of an energy-saving low-carbon society, we have utilized the field emission (FE) characteristics of highly crystalline single-walled carbon nanotubes (HC-SWCNTs), which are synthesized by arc discharge, purified, and annealed at high temperatures, to form an excellent electron emission layer with high current density and high durability. The thin films containing HC-SWCNTs exhibit electrical properties that result in almost no heat generation at high current densities (i.e., high power densities). When the thin films fabricated in this research were used in a power switching device, the FE characteristics of HC-SWCNTs as an electron source in the device were applied to switch the ampere-order currents on and off. Owing to their high crystallinity, SWCNTs exhibit potentials close to the ideal conductive characteristics, and their performance is expected to meet the requirements of high-power density, zero energy loss, and high-frequency responses, even when compared with power devices fabricated using semiconductors, for example, SiC and GaN. Therefore, the purpose of this research is to establish a high-power-density and low-energy-loss thin-film formation technology and to develop a high-performance switching device.

Addressing the root cause of calcite precipitation that leads to energy loss in geothermal systems

Geothermal sources are an essential energy resource in many cities around the world, in which a deep hot water reservoir has two energetic bases: thermal and hydraulic. The use of this energy can produce both electricity and heat. A geothermal well is a way in which the energy flows from the reservoir to the surface. A known operational problem can directly consume hydraulic energy and indirectly consume thermal energy. Calcium carbonate (CaCO3) precipitation and scaling can reduce and even block the flow area of a geothermal well, deferring, degrading, or even closing the production of water, steam, heat, and power. CO2 degassing, which is intrinsic to the deepwater system, is often the cause of this problem. This relationship is evident in the chemical balance: Ca2+(aq) + 2 HCO3–(aq) ⇆ H2O + CaCO3(s) + CO2(aq). With the head loss provided by the water flow, CO2(aq) changes to the gaseous state (CO2(aq) → CO2(g)), which disfavors the CaCO3 dissolution and implies its mineralization. The CO2(aq) closely links the two mentioned chemical reactions and makes them mutually dependent. Therefore, two causes favor the CaCO3 precipitation: changes in thermodynamic conditions (pressure and temperature) and CO2 exsolution. It takes place even if the hot water is not boiling or flashing. This paper aims to quantify these two causes by applying our techniques in some geothermal fields in different locations in the world. In all scenarios investigated, the release of CO2 contributes from 66.1% to 92.6% of the CaCO3 precipitation. These results can lead engineers to adequately remedy the problem and suitably design and operate a geothermal system as a whole.

Minimization of surface roughness in 5-axis milling of turbine blades

The Reynolds number of turbine blades can be reduced by decreasing the surface roughness of the blades, which decreases energy loss in energy production systems. Due to the challenges of the polishing process in reducing roughness of machined blades, the application of optimized machining parameters to decrease surface roughness is a practical solution. Virtual machining system is explored in this research to improve the efficiency of machined parts. The aim of this research is to provide a virtual machining system that can predict and effectively reduce roughness in gas turbine blade 5-axis machining operations. The machining parameters were optimized using Genetic algorithm to reduce surface roughness. The turbine blades were machined using a 5-axis CNC machine tool, and the surface roughness of the machined parts was measured using a CMM machine to validate the developed methodology in the study. The optimized machining parameters result in a 26.2% reduction in observed surface roughness and a 27.3% reduction in expected surface roughness in the machined blades. The developed virtual machining system can be used to improve the surface quality of machined turbine blades and hence improve the efficiency of gas turbines during the power production in gas turbines.

Heat Loss Due to Domestic Hot Water Pipes

Domestic hot water (DHW) system energy losses are an important part of energy consumption in newly built or in reconstructed apartment buildings. To reach nZEB or low energy building targets (renovation cases) we should take these losses into account during the design phase. These losses depend on room and water temperature, insulation and length of pipes and water circulation strategy. The target of our study is to develop a method which can be used in the early stages of design in primary energy calculations. We are also interested in how much of these losses cannot be utilised as internal heat gain and how much heat loss depends on the level of energy performance of the building. We used detailed DHW system heat loss measurements and simulations from an nZEB apartment building and annual heat loss data from a total of 22 apartment buildings. Our study showed that EN 15316-3 standard equations for pipe length give more than a twice the pipe length in basements. We recommend that for pipe length calculation in basements, a calculation based on the building’s gross area should be used and for pipe length in vertical shafts, a building’s heating area-based calculation should be used. Our study also showed that up to 33% of pipe heat losses can be utilised as internal heat gain in energy renovated apartment buildings but in unheated basements this figure drops to 30% and in shafts rises to 40% for an average loss (thermal pipe insulation thickness 40 mm) of 10.8 W/m and 5.1 W/m. Unutilised delivered energy loss from DHW systems in smaller apartment buildings can be up to 12.1 kWh/(m2·a) and in bigger apartment buildings not less than 5.5 kWh/(m2·a) (40 mm thermal pipe insulation).